There is a holocaust happening. Right now. And it's not confined to one nation or even one region. It is a global crisis.

Species are going extinct en masse.

Every 20 minutes we lose an animal species. If this rate continues, by century's end, 50% of all living species will be gone. It is a phenomenon known as the sixth extinction. The fifth extinction took place 65 million years ago when a meteor smashed into the Earth, killing off the dinosaurs and many other species and opening the door for the rise of mammals. Currently, the sixth extinction is on track to dwarf the fifth.

What -- or more correctly -- who is to blame this time? As Pogo said, "We have met the enemy, and he is us."

The causes of this mass die-off are many: overpopulation, loss of habitat, global warming, species exploitation (the black market for rare animal parts is the third-largest illegal trade in the world, outranked only by weapons and drugs). The list goes on, but it all points to us.

Over the last 15 years, in the course of producing television documentaries and writing about wildlife, I have traveled the globe, and I have witnessed the grim carnage firsthand. I've observed the same story playing out in different locales.

In South Africa, off the coast of Cape Horn, lives one of the most feared predators of all -- the great white shark. Yet this awesome creature is powerless before the mindless killing spree that is decimating its species at the jaw-dropping rate of 100 million sharks a year. Many are captured so that their dorsal fins can be chopped off (for shark fin soup). Then, still alive, they are dropped back into the sea, where they die a slow and painful death.

Further east, in Indonesia, I witnessed the mass destruction of rain forests to make way for palm oil plantations. Indonesia is now the world's leading producer of palm oil -- a product used in many packaged foods and cosmetic goods -- and the victims are the Sumatran elephant and orangutan. These beautiful creatures are on the brink of extinction as their habitats go up in smoke, further warming our planet in the process.

One day while swimming off the coast of Indonesia, I came across a river of refuse and raw sewage stretching for miles. These streams and islands of refuse now populate all our oceans; in the middle of the Pacific, there is an island of garbage the size of Texas. This floating pollution serves to choke off and kill sea turtles -- driving them closer to extinction. At the same time, the coral reefs where sea turtles get their food supply are dying due to rising sea temperatures from global warming. To top it off, sea turtles are hunted and killed for their meat -- considered a delicacy in many Asian countries. It is an ugly but altogether effective one-two-three punch for this unique species.

It's important to understand that this is not just a race to save a handful of charismatic species -- animals to which we attach human-inspired values or characteristics. Who wouldn't want to save the sea otter, polar bear, giant panda or gorilla? These striking mammals tug at our heartstrings and often our charitable purse strings. But our actions need to be just as swift and determined when it comes to the valley elderberry longhorn beetle or the distinctly uncuddly, pebbly-skinned Puerto Rican crested toad or the black-footed ferret, whose fate is inextricably intertwined with that of the prairie dog. The reality is that each species, no matter how big, small, friendly or vicious, plays an important and essential role in its ecosystem. And we're in a race to preserve as much of the animal kingdom as possible.

Meanwhile, around the planet there are massive die-offs of amphibians, the canaries in our global coal mine. When frogs and other amphibians, which have existed for hundreds of millions of years, start to vanish, it is a sign that our natural world is in a state of peril. Bat and bee populations are also being decimated. Without bees, there will be no pollination, and without pollination, the predator that is decimating these other species -- humankind -- will also be headed toward its own extinction. Yes, there is a certain irony there.

This was all brought home to me in an intimate way after a recent trip to Panama. My young daughter, Maya, asked if she could accompany me on my next trip there so that she could see one of her favorite animals -- the frog -Panamanian golden frog -- up close and personal in the jungle. Sadly, I had to tell her no. This small, beautiful frog -- the national symbol of Panama -- no longer exists in the wild. Only a few live in captivity.

Is there hope? Yes. Because in every place I visited to witness the sixth extinction unfold, I met brave and selfless conservationists, biologists and wildlife scientists working hard to save species.

In Panama, biologist Edgardo Griffith has set up an amphibian rescue center to protect and quarantine rare frogs (including the Panamanian golden frog) before they are all wiped out by the deadly fungus Chytrid, which is rapidly killing off frogs on a global scale. In Africa, zoologist Iain Douglas Hamilton is one of many seeking to stop the illegal trade in elephant ivory and rhino horn. In Namibia, zoologist Laurie Marker is making strides to save the cheetah before it goes the way of the saber tooth tiger (or India's Bengal tiger, which is also on the precipice of extinction). In Indonesia, Ian Singleton is raising orphaned orangutans, training them to return to the remaining rain forest -- giving them a second chance at living in the wild. In South Africa, Alison Kock is leading a crusade to educate the world about the wholesale destruction of sharks.

Here in the United States, Chris Lucash of the U.S. Fish and Wildlife Service, is working to reintroduce the red wolf, now found only in captivity, to the woods of North Carolina. They are just a few of the many who are trying to reverse the species holocaust that threatens the future of our natural world.

These committed scientists bring great generosity and devotion to their respective efforts to stop the sixth extinction. But if we don't all rise to the cause and join them in action, they cannot succeed. The hour is near, but it's not too late.

Jeff Corwin is the author of "100 Heartbeats," a book about his experiences tracking the sixth extinction.